Summary

Efficacy of compounds was investigated in field experiments in Denmark and the Netherlands according to EPPO guidelines. Some Yucca extracts and potassium bicarbonate had an efficacy similar to sulphur on leaves. Addition of sulphur to Yucca 1 and to potassium bicarbonate increased the level of efficacy to that of copper. This confirms results from earlier years. Although a dose increase resulted in better efficacy, this was more prominent for Yucca1 than for potassium bicarbonate.

The final version of this paper is published in: Niggli, Urs; Leifert, Carlo; Alföldi, Thomas; Lück, Lorna and Willer, Helga, Eds. (2007) Improving Sustainability in Organic and Low Input Food Production Systems. Proceedings of the 3rd International Congress of the European Integrated Project Quality Low Input Food (QLIF). University of Hohenheim, Germany, March 20 – 23, 2007. Research Institute of Organic Agriculture FiBL, CH-Frick.http://orgprints.org/10417/ Printed copies may be ordered from the FiBL Shop at www.shop.fibl.org.